InfoWorld's Peter Wayner takes a look at 13 open source development projects making waves in the enterprise. From Git to Hadoop to build management tools, "even in the deepest corners of proprietary stacks, open source tools can be found, often dominating. The reason is clear: Open source licenses are designed to allow users to revise, fix, and extend their code. The barber or cop may not be familiar enough with code to contribute, but programmers sure know how to fiddle with their tools. The result is a fertile ecology of ideas and source code, fed by the enthusiasm of application developers who know how to 'scratch an itch'."